In July 1979 it was discovered that a group of infants who were receiving Neo-Mull-Soy formula were not behaving and developing according to normative expectations and were exhibiting a "failure to thrive" type syndrome. Analysis of this infant formula revealed that it was deficient in chloride and that many of the infants fed this formula were suffering from metabolic alkalosis and chloride and potassium deficiencies. Changes to a properly balanced formula improved their condition. There is some question, however, whether or not any permanent organic damage was sustained. These infants will be studied for a five year period to investigate the possibility of long-term effects from this dietary deficiency. Our research will focus on whether intellectual, behavioral, and child rearing practices were either directly and indirectly affected by the metabolic abnormalities produced from the use of this chloride deficient formula.